Hydrochloric Acid → HCID 9992929, compound

Participants

Reaction Steps

Cyclohexanoyl chloride (32.7 mL, 232 mmole) was added dropwise to a solution of (L)-leucine (37 g, 282 mmole) in aqueous sodium hydroxide (500 mL, 2 N). During the course of this addition, the reaction temperature was maintained below 45° C. using an ice/water bath, as necessary. The pH was maintained at about 10 by the addition of aliquots of 14 N NaOH, as necessary. After the addition was complete, the reaction mixture was stirred for an additional 2 hours at room temperature. The resulting clear solution was adjusted to pH 2.5 by the dropwise addition of concentrated hydrochloric acid. The precipitate was collected by filtration, re-dissolved in a minimum amount of 12 N sodium hydroxide, and re-precipitated by dropwise addition of concentrated hydrochloric acid and filtered. The crude reaction product was a white solid and contained about 85% N-cyclohexanoyl leucine sodium salt, about 10% cyclohexane carboxylic acid sodium salt, and about 5% N-cyclohexanoylleucylleucine sodium salt, by weight. The solid was washed with dilute aqueous hydrochloric acid (750 mL, 0.1 N) to provide N-cyclohexanoyl-(L)-leucine as a white crystalline solid (52.6 g, 77%).

Provenance & Evidence